fix(desktop): Lotus links use the public web app, and open in-app (#248)

Lotus permalinks (#130) were built from window.location.origin. In the
desktop app that's the local tauri-plugin-localhost server (hash-routed), so
"Copy Lotus Link" copied e.g. http://localhost:…/#/home/!room…, which works
for nobody else. And the link recogniser only knew that local base, so a real
https://chat.lotusguild.org/home/… link in a message opened the browser
instead of the room.

- useLotusShareBase: in the desktop app, links for other people use config
  `webAppUrl` (https only, set by cinny-desktop #23) in web path-routing
  form; otherwise the origin, as before. Used by "Copy Lotus Link" on
  messages, the space menu and space tabs.
- The recogniser accepts several bases: the origin, plus `webAppUrl` in the
  desktop app.
- The web app is unchanged.

Verified with a simulated desktop (Tauri bridge + webAppUrl) against a local
Synapse. Copied links are https://chat.lotusguild.org/home/<room>/<event> and
https://chat.lotusguild.org/<space>. A public link in a message renders as
the room pill and clicking it opens the room in-app, with nothing sent to the
system browser. The web app still copies origin links. Unit tests for the
base selection; Playwright 20 passed.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01PPmy3tPq869XDW4njjVaKA

src/app/features/room/message/Message.tsx

@@ -83,8 +83,6 @@ import { copyToClipboard } from '../../../utils/dom';
 import { stopPropagation } from '../../../utils/keyboard';
 import { getMatrixToRoomEvent } from '../../../plugins/matrix-to';
 import { getLotusRoomPermalink } from '../../../plugins/lotus-permalink';
-import { getOriginBaseUrl } from '../../../pages/pathUtils';
-import { useClientConfig } from '../../../hooks/useClientConfig';
 import { getViaServers } from '../../../plugins/via-servers';
 import { useMediaAuthentication } from '../../../hooks/useMediaAuthentication';
 import { useRoomPinnedEvents } from '../../../hooks/useRoomPinnedEvents';
@@ -98,6 +96,7 @@ import { useLongPress } from '../../../hooks/useLongPress';
 import { ActionSheet } from '../../../components/action-sheet';
 import { useBookmarks } from '../../../hooks/useBookmarks';
 import { PresenceRingAvatar } from '../../../components/presence';
+import { useLotusShareBase } from '../../../hooks/useLotusLinkBase';
 import { AvatarDecoration } from '../../../components/avatar-decoration/AvatarDecoration';
 
 // Delivery status indicator for own messages
@@ -460,18 +459,11 @@ export const MessageCopyLotusLinkItem = as<
     onClose?: () => void;
   }
 >(({ room, mEvent, onClose, ...props }, ref) => {
-  const { hashRouter } = useClientConfig();
+  const lotusBase = useLotusShareBase();
   const handleCopy = () => {
     const eventId = mEvent.getId();
     if (!eventId) return;
-    copyToClipboard(
-      getLotusRoomPermalink(
-        getOriginBaseUrl(hashRouter),
-        room.roomId,
-        eventId,
-        getViaServers(room),
-      ),
-    );
+    copyToClipboard(getLotusRoomPermalink(lotusBase, room.roomId, eventId, getViaServers(room)));
     onClose?.();
   };
 

src/app/hooks/useLotusLinkBase.test.ts

@@ -0,0 +1,23 @@
+import { test } from 'node:test';
+import assert from 'node:assert/strict';
+import { lotusLinkBases, lotusShareBase } from './useLotusLinkBase';
+
+const LOCAL = 'http://localhost:44548/#/';
+const WEB = 'https://chat.lotusguild.org';
+
+test('web: shared links use the page origin', () => {
+  assert.equal(lotusShareBase(WEB, false, WEB), WEB);
+  assert.deepEqual(lotusLinkBases(WEB, false, undefined), [WEB]);
+});
+
+test('desktop with webAppUrl: shared links use the public web app', () => {
+  assert.equal(lotusShareBase(LOCAL, true, `${WEB}/`), WEB);
+  assert.deepEqual(lotusLinkBases(LOCAL, true, WEB), [LOCAL, WEB]);
+});
+
+test('desktop without a valid webAppUrl falls back to the origin', () => {
+  [undefined, '', 'http://chat.lotusguild.org', 'nonsense'].forEach((v) => {
+    assert.equal(lotusShareBase(LOCAL, true, v), LOCAL, String(v));
+    assert.deepEqual(lotusLinkBases(LOCAL, true, v), [LOCAL]);
+  });
+});

src/app/hooks/useLotusLinkBase.ts

@@ -0,0 +1,37 @@
+import { useMemo } from 'react';
+import { useClientConfig } from './useClientConfig';
+import { isTauri } from './useTauri';
+import { getOriginBaseUrl } from '../pages/pathUtils';
+import { resolveWebAppUrl } from '../utils/callInBrowser';
+
+/**
+ * [Gitea #248] Base URL for Lotus links meant for other people.
+ *
+ * On the web that's this page's origin. In the desktop app the page is served
+ * from a local address (and hash-routed), which nobody else can open, so use
+ * the public web app from config `webAppUrl` (web path routing) instead.
+ * Without a valid `webAppUrl` it falls back to the origin, as before.
+ */
+export const lotusShareBase = (originBase: string, desktop: boolean, webAppUrl: unknown): string =>
+  (desktop && resolveWebAppUrl(webAppUrl)) || originBase;
+
+/**
+ * Every base a Lotus link to this deployment may start with: the origin, plus
+ * the public web app in the desktop app, so a shared https link opens in-app.
+ */
+export const lotusLinkBases = (
+  originBase: string,
+  desktop: boolean,
+  webAppUrl: unknown,
+): string[] => {
+  const shared = lotusShareBase(originBase, desktop, webAppUrl);
+  return shared === originBase ? [originBase] : [originBase, shared];
+};
+
+export const useLotusShareBase = (): string => {
+  const { hashRouter, webAppUrl } = useClientConfig();
+  return useMemo(
+    () => lotusShareBase(getOriginBaseUrl(hashRouter), isTauri(), webAppUrl),
+    [hashRouter, webAppUrl],
+  );
+};

src/app/pages/client/ClientNonUIFeatures.tsx

@@ -77,6 +77,7 @@ import { KeyboardShortcutsDialog, useKeyboardShortcutsTrigger } from '../../feat
 import { useRoomsListener } from '../../hooks/useRoomsListener';
 import { threadNotificationsAtom } from '../../state/threadNotifications';
 import { roomIdToActiveThreadIdAtomFamily } from '../../state/room/thread';
+import { lotusLinkBases } from '../../hooks/useLotusLinkBase';
 import {
   getThreadNotificationMode,
   shouldNotifyThreadReply,
@@ -118,11 +119,12 @@ function SystemEmojiFeature() {
 
 // [Gitea #103] Mirror the privacy toggle into the html parser's module flag.
 function LotusPermalinkFeature() {
-  const { hashRouter } = useClientConfig();
+  const { hashRouter, webAppUrl } = useClientConfig();
   useEffect(() => {
-    setLotusPermalinkBase(getOriginBaseUrl(hashRouter));
+    // [Gitea #248] In the desktop app, links to the public web app count too.
+    setLotusPermalinkBase(lotusLinkBases(getOriginBaseUrl(hashRouter), isTauriApp(), webAppUrl));
     return () => setLotusPermalinkBase(undefined);
-  }, [hashRouter]);
+  }, [hashRouter, webAppUrl]);
   return null;
 }
 

src/app/pages/client/sidebar/SpaceTabs.tsx

@@ -49,13 +49,7 @@ import { roomToParentsAtom } from '../../../state/room/roomToParents';
 import { allRoomsAtom } from '../../../state/room-list/roomList';
 import { useAnyRoomLiveCall } from '../../../hooks/useSpaceLiveCall';
 import { LiveDot } from './SpaceTabs.css';
-import {
-  getOriginBaseUrl,
-  getSpaceLobbyPath,
-  getSpacePath,
-  joinPathComponent,
-} from '../../pathUtils';
-import { useClientConfig } from '../../../hooks/useClientConfig';
+import { getSpaceLobbyPath, getSpacePath, joinPathComponent } from '../../pathUtils';
 import {
   SidebarAvatar,
   SidebarItem,
@@ -102,6 +96,7 @@ import { settingsAtom } from '../../../state/settings';
 import { useOpenSpaceSettings } from '../../../state/hooks/spaceSettings';
 import { useRoomCreators } from '../../../hooks/useRoomCreators';
 import { useRoomPermissions } from '../../../hooks/useRoomPermissions';
+import { useLotusShareBase } from '../../../hooks/useLotusLinkBase';
 import { InviteUserPrompt } from '../../../components/invite-user-prompt';
 
 type SpaceMenuProps = {
@@ -112,7 +107,7 @@ type SpaceMenuProps = {
 const SpaceMenu = forwardRef<HTMLDivElement, SpaceMenuProps>(
   ({ room, requestClose, onUnpin }, ref) => {
     const mx = useMatrixClient();
-    const { hashRouter } = useClientConfig();
+    const lotusBase = useLotusShareBase();
     const [hideActivity] = useSetting(settingsAtom, 'hideActivity');
     const roomToParents = useAtomValue(roomToParentsAtom);
     const powerLevels = usePowerLevels(room);
@@ -152,9 +147,7 @@ const SpaceMenu = forwardRef<HTMLDivElement, SpaceMenuProps>(
     const handleCopyLotusLink = () => {
       const roomIdOrAlias = getCanonicalAliasOrRoomId(mx, room.roomId);
       const viaServers = isRoomAlias(roomIdOrAlias) ? undefined : getViaServers(room);
-      copyToClipboard(
-        getLotusSpacePermalink(getOriginBaseUrl(hashRouter), roomIdOrAlias, viaServers),
-      );
+      copyToClipboard(getLotusSpacePermalink(lotusBase, roomIdOrAlias, viaServers));
       requestClose();
     };
 

src/app/pages/client/space/Space.tsx

@@ -39,13 +39,7 @@ import {
   NavItemContent,
   NavLink,
 } from '../../../components/nav';
-import {
-  getOriginBaseUrl,
-  getSpaceLobbyPath,
-  getSpaceRoomPath,
-  getSpaceSearchPath,
-} from '../../pathUtils';
-import { useClientConfig } from '../../../hooks/useClientConfig';
+import { getSpaceLobbyPath, getSpaceRoomPath, getSpaceSearchPath } from '../../pathUtils';
 import { getCanonicalAliasOrRoomId, isRoomAlias } from '../../../utils/matrix';
 import { useSelectedRoom } from '../../../hooks/router/useSelectedRoom';
 import {
@@ -92,6 +86,7 @@ import { ContainerColor } from '../../../styles/ContainerColor.css';
 import { AsyncStatus, useAsyncCallback } from '../../../hooks/useAsyncCallback';
 import { BreakWord } from '../../../styles/Text.css';
 import { InviteUserPrompt } from '../../../components/invite-user-prompt';
+import { useLotusShareBase } from '../../../hooks/useLotusLinkBase';
 import { useCallEmbed } from '../../../hooks/useCallEmbed';
 
 type SpaceMenuProps = {
@@ -100,7 +95,7 @@ type SpaceMenuProps = {
 };
 const SpaceMenu = forwardRef<HTMLDivElement, SpaceMenuProps>(({ room, requestClose }, ref) => {
   const mx = useMatrixClient();
-  const { hashRouter } = useClientConfig();
+  const lotusBase = useLotusShareBase();
   const [hideActivity] = useSetting(settingsAtom, 'hideActivity');
   const [developerTools] = useSetting(settingsAtom, 'developerTools');
   const roomToParents = useAtomValue(roomToParentsAtom);
@@ -137,9 +132,7 @@ const SpaceMenu = forwardRef<HTMLDivElement, SpaceMenuProps>(({ room, requestClo
   const handleCopyLotusLink = () => {
     const roomIdOrAlias = getCanonicalAliasOrRoomId(mx, room.roomId);
     const viaServers = isRoomAlias(roomIdOrAlias) ? undefined : getViaServers(room);
-    copyToClipboard(
-      getLotusSpacePermalink(getOriginBaseUrl(hashRouter), roomIdOrAlias, viaServers),
-    );
+    copyToClipboard(getLotusSpacePermalink(lotusBase, roomIdOrAlias, viaServers));
     requestClose();
   };
 

src/app/plugins/react-custom-html-parser.tsx

@@ -122,11 +122,15 @@ const cleanHref = (href: string): string =>
   stripTrackingOnRender ? stripTrackingParams(href) : href;
 
 // [Gitea #130] Links to THIS deployment's room routes render and click like
-// matrix.to links. The base is set once from the client config
-// (ClientNonUIFeatures) because this module has no access to hooks.
-let lotusPermalinkBase: string | undefined;
-export const setLotusPermalinkBase = (baseUrl: string | undefined): void => {
-  lotusPermalinkBase = baseUrl;
+// matrix.to links. The bases are set once from the client config
+// (ClientNonUIFeatures) because this module has no access to hooks. [Gitea
+// #248] Several: the desktop app knows both its local origin and the public web
+// app (`webAppUrl`), and people share the public one.
+let lotusPermalinkBases: string[] = [];
+export const setLotusPermalinkBase = (baseUrls: string | string[] | undefined): void => {
+  lotusPermalinkBases = (Array.isArray(baseUrls) ? baseUrls : [baseUrls]).filter(
+    (b): b is string => !!b,
+  );
 };
 /**
  * The matrix.to form of `href` when it is a matrix.to link or a Lotus
@@ -134,7 +138,11 @@ export const setLotusPermalinkBase = (baseUrl: string | undefined): void => {
  */
 export const toMatrixToHref = (href: string): string | undefined => {
   if (testMatrixTo(href)) return href;
-  return lotusPermalinkBase ? lotusPermalinkToMatrixTo(lotusPermalinkBase, href) : undefined;
+  for (const base of lotusPermalinkBases) {
+    const matrixTo = lotusPermalinkToMatrixTo(base, href);
+    if (matrixTo) return matrixTo;
+  }
+  return undefined;
 };
 
 export const LINKIFY_OPTS: LinkifyOpts = {